Joe Wright may well be the most overrated as well as the most feted young British directors working today. His films are visually slick and fast moving, but trite and pretentious as if made by a precocious teenager desperate for people to know he is "cool".

Something about Wright's directing style brings out the worse in even the best actors. In The Soloist, he elicited depressingly heavy handed performances from Jamie Foxx and Robert Downey Jr. In Hanna, a thriller with a science-fiction premise, he gets Cate Blanchett, one of the finest actors working today, whom I had thought incapable of a bad performance, to go embarrassingly over the top as his villain.

Tom Hollander is equally bad as Isaacs, her gay, sadistic German enforcer - a nasty old stereotype that would get homosexual rights groups demonstrating outside Universal's offices, if Wright were not so beloved of the London media establishment.

One person whose talent is not corrupted by Wright's crude sensibility is the film's teenaged star, Saoirse Ronan, who won an Academy Award nomination for her work in Wright's film, Atonement.

She plays Hanna, who is first encountered hunting reindeer in a gorgeously photographed Finnish landscape. A strange, barely pubescent girl - with her white-blonde hair and pale skin she looks like a hybrid of Blanchett and Tilda Swinton - she lives in a crude cabin with her gloomy, Germanic father, Erik (Eric Bana).

Joe Wright's directing style brings out the worse in even the best actors

Their life together in the frozen wastes is mostly spent in combat training: he is making his daughter into the perfect assassin. This is in preparation for the day when she goes out into the world to assassinate Marissa (Blanchett), the woman who killed Erik's wife, her mother.

In the meantime he has taught his daughter seven languages, multiple false back stories and all the bland scientific facts that can be found in an encyclopedia. She has, however, never heard music or used electricity (setting up clunky scenes of discovery to come).

Erik, who is a apparently a former CIA agent gone into hiding, puts the plot in motion by letting headquarters know he is still alive. Helicopters and scary commandos arrive above the cabin in a strange echo of this weeks news of the killing of Osama bin Laden - except that in this film with its Avatar-style idiot-left politics, it is taken for granted that the American commandos are bad.

Hanna is taken to a sinister underground prison whose attractively curving concrete corridors make it look like something a British architect might design for a national theatre. With pounding music (by the Chemical Brothers) amping up the tension, she quickly demonstrates her deadly skills and ruthlessness before escaping through conveniently sized ventilation tubes and climbing out into a gorgeous desert landscape.

It turns out to be Morocco, where she manages to hide in the dormobile of some hippy-ish English tourists (the engaging Olivia Williams and Jason Flemyng).

Melissa, however, is after her (and also Eric, who escaped capture at the cabin).

So Hanna, who has befriended the hippy tourists, has also put them in grave danger. And as their dormobile heads to northern Europe, she and her friends are tracked by Isaacs and his gang of German skinheads.

But at a certain point, it becomes less clear who are the hunters and who is the hunted.

The idea of the family is made to represent "Good" in the crudest possible way and in stark contrast to the skinheads and the evil, technologically inclined CIA agents whom Hanna dispatches in large, anonymous numbers.

You can tell that Blanchett's Melissa is super evil because she has a strong - and ridiculous - Southern accent, because she manically cleans her gleaming teeth, and because she is just the kind of bitter, childless spinster who would be in charge of a secret breeding programme for super warriors.

If the action scenes are reminiscent of the Bourne films - though less believable - Hanna manages to make those movies seem wonderfully grown-up and subtle.

The best thing about the film, besides its beautful landscapes, is a supporting performance by Jessica Barden - who was also terrific in Tamara Drewe - as a celebrity-obsessed English teenager who makes friends with Hanna.